02175nas a2200253   4500008004100000022001400041245011500055210006900170260008000239300001400319490000800333520125000341653002001591653002101611653001901632653000901651653002601660653001201686100002501698700001801723700001901741700003001760856013101790       2008                        eng d  a1618-264200aImaging the stomatal physiology of somatic embryo-derived peanut leaves by scanning electrochemical microscopy0 aImaging the stomatal physiology of somatic embryoderived peanut   aTIERGARTENSTRASSE 17, D-69121 HEIDELBERG, GERMANYbSPRINGER HEIDELBERGcJUL  a2227-22330 v3913 a<p>The stomatal physiology, chlorophyll distribution and photosynthetic activity of somatic embryo (SE)- and seedling-derived peanut plants grown in vitro (test tube-grown) and extra vitrum (soil-grown) are investigated using scanning electrochemical microscopy (SECM). This SECM imaging is performed in two different feedback modes, corresponding to oxygen evolution and chlorophyll distribution. More specifically, the oxygen evolution profiles of the in vitro leaves indicate important differences in leaf anatomy between the SE- and seedling-derived leaves. On the other hand, the chlorophyll distribution images show individual stomata of size ca. 27 +/- 5 mu m. Further studies on senescing (aged) leaves reveal interesting voltammograms that vary widely over the stomatal complexes and the surrounding tissues, probably due to the release of electroactive metabolites during chlorophyll breakdown when the leaves turn yellow. Thus, the present investigation could open up new opportunities for characterizing botanical systems using electroanalytical techniques. In addition, it could provide further insights into various areas of current relevance, including signal transduction, cell fate/differentiation and developmental biology.</p>10aleaf senescence10aoxygen evolution10aphotosynthesis10aSECM10asomatic embryogenesis10astomata1 aParthasarathy, Meera1 aSingh, Shweta1 aHazra, Sulekha1 aPillai, Vijayamohanan, K.  uhttps://library.ncl.res.in/content/imaging-stomatal-physiology-somatic-embryo-derived-peanut-leaves-scanning-electrochemical-002367nas a2200217   4500008004100000022001400041245015500055210006900210260010200279300001200381490000800393520150000401653002301901653001201924653001101936653001301947653000901960100002501969700003001994856012502024       2009                        eng d  a0253-413400aImaging hydrogen oxidation activity of catalyst-coated perfluoro sulfonic acid-polymer electrolyte membranes using scanning electrochemical microscopy0 aImaging hydrogen oxidation activity of catalystcoated perfluoro   aC V RAMAN AVENUE, SADASHIVANAGAR, P B \#8005, BANGALORE 560 080, INDIAbINDIAN ACAD SCIENCEScSEP  a719-7250 v1213 a<p>Scanning Electrochemical Microscopy (SECM) is a unique technique for studying fast heterogeneous kinetics and to map reactivity gradients along the surface of an electrocatalyst, especially when it involves multiple surface sites of varying reactivity. It combines the dual advantages offered by ultramicroelectrode (UME) voltammetry in terms of reduced ohmic drop and insignificant double layer charging contribution with the advantages of imaging by rastering the UME across an electro-active surface. In this work, we demonstrate these distinctive features of SECM in evaluating reactivity gradients on catalyst (Pt/C) coated NafionA (R) films towards hydrogen oxidation activity, a reaction of immense technological relevance. Imaging has been performed in the feedback mode by allowing H(2) evolution at the tip (25 A mu m Pt UME), which is reoxidized at the substrate electrode containing Pt/C-Nafion film. Interesting distribution in H(2) oxidation activity has been observed as a function of potential applied to the Pt/C-Nafion film. In addition, a plot of normalized tip current versus the substrate electrode potential indicates the effect of potential-induced reactivity change in the catalyst-coated membranes. The results of the present investigation are believed to be useful to H(2)/O(2) PEM fuel cells with respect to evaluating reactivity gradients of catalyst-coated polymer electrolyte membranes, which is important to rectify problems related to catalyst utilization.</p>10ahydrogen oxidation10aImaging10aNafion10aplatinum10aSECM1 aParthasarathy, Meera1 aPillai, Vijayamohanan, K.  uhttps://library.ncl.res.in/content/imaging-hydrogen-oxidation-activity-catalyst-coated-perfluoro-sulfonic-acid-polymer-0